Molecular Mechanisms of Zinc as a Pro-Antioxidant Mediator: Clinical Therapeutic Implications

Prospective association between baseline plasma zinc concentration and development of proteinuria in Chinese hypertensive patients

OBJECTIVE

We aimed to evaluate the association between baseline plasma zinc and the development of proteinuria as well as possible effect modifiers in hypertensive patients.

METHODS

This is a subset of the China Stroke Primary Prevention Trial (CSPPT) Renal Sub-Study. In the CSPPT, participants were randomized to receive a daily oral dose of 1 tablet containing 10 mg enalapril and 0.8 mg folic acid or 1 tablet containing 10 mg enalapril only. A total of 783 participants with plasma zinc measurements and without proteinuria at baseline were included in the current study. The study outcome was the development of proteinuria during the follow-up, defined as a urine dipstick reading of trace or ≥1+ at the exit visit.

RESULTS

During a median follow-up duration of 4.4 years, the development of proteinuria occurred in 93 (11.9 %) participants. There was an inverse relation of baseline plasma zinc with the development of proteinuria (per SD increment; OR, 0.74, 95 % CI: 0.55-0.99), p for trend of quartiles = 0.005.

CONCLUSIONS

In Chinese hypertensive patients, there was a significant inverse association between baseline plasma zinc and the development of proteinuria, although plasma zinc remained in the reference range.

Nutritional Supplements for the Treatment of Neuropathic Pain

Neuropathic pain affects 7-10% of the population and is often ineffectively and incompletely treated. Although the gold standard for treatment of neuropathic pain includes tricyclic antidepressants (TCAs), serotonin-noradrenaline reuptake inhibitors, and anticonvulsants, patients suffering from neuropathic pain are increasingly turning to nonpharmacologic treatments, including nutritional supplements for analgesia. So-called "nutraceuticals" have garnered significant interest among patients seeking to self-treat their neuropathic pain with readily available supplements. The supplements most often used by patients include vitamins such as vitamin B and vitamin D, trace minerals zinc and magnesium, and herbal remedies such as curcumin and St. John's Wort. However, evidence surrounding the efficacy and mechanisms of these supplements in neuropathic pain is limited, and the scientific literature consists primarily of preclinical animal models, case studies, and small randomized controlled trials (RCTs). Further exploration into large randomized controlled trials is needed to fully inform patients and physicians on the utility of these supplements in neuropathic pain. In this review, we explore the basis behind using several nutritional supplements commonly used by patients with neuropathic pain seen in rheumatology clinics.

Trace elements exposure and risk in age-related eye diseases: a systematic review of epidemiological evidence

This systematic review aimed to evaluate existing evidence on the associations between trace elements exposure and age-related eye diseases. PubMed and Google scholar databases were searched for epidemiological and postmortem studies on the relationship between exposure to trace elements and Age-related eye diseases such as age-related macular degeneration (AMD), cataract, glaucoma and diabetic retinopathy (DR), in population groups aged 40 years and above. Available evidence suggests that cadmium (Cd) exposure may be positively associated with the risks of AMD and cataract. There is also evidence that exposure to lead (Pb) may be positively associated with higher risk of cataract and glaucoma. There is limited number of relevant studies and lack of prospective studies for most of the investigated associations. Evidence for other trace elements is weak and inconsistent, and the number of available studies is small. Likewise, there are very few relevant studies on the role of trace elements in DR. Chemical elements that affect the distribution and absorption of other trace elements have never been investigated. The suggestive but limited evidence motivates large and quality prospective studies to fully characterize the impact of exposure to trace (toxic and essential) elements on age-related eye diseases.

Evaluation of biomarkers related to zinc nutritional status, antioxidant activity and oxidative stress in rheumatoid arthritis patients

BACKGROUND

Oxidative stress (OS) is an important process related to the pathophysiology of rheumatoid arthritis and can be increased by the low intake of antioxidants. Zinc (Zn) is an important antioxidant trace-element for human health and the assessment of the nutritional status of this micronutrient in these patients is of relevance.

AIM

This study aimed to evaluate Zn nutritional status in rheumatoid arthritis patients and its relation to OS.

METHODS

A case-control study was carried out with 51 patients diagnosed with rheumatoid arthritis (RA group) recruited in Hospital São Paulo (São Paulo, Brazil) and 55 healthy women (CO group) from the campus of the University of São Paulo. Blood and 24-hour urine collection were used for biochemical parameters related to Zn status and OS. The assessment of dietary Zn was performed by three 24-hour dietary recalls.

RESULTS

The RA group presented significative low Zn intake (p < 0.001) and plasma concentration (p = 0.040) of this mineral compared to the CO group. However, both groups were Zn deficient and the disease activity (DAS28 score) for RA patients did not influence Zn biomarkers. In addition, the antioxidant enzymes (superoxide dismutase and glutathione peroxidase) activity and the urinary 8-isoprostanes were reduced in RA patients.

CONCLUSION

The evaluation of dietary intake and biochemical biomarkers indicates that rheumatoid arthritis patients are zinc deficient and have increased OS.

Association of Zinc Deficiency with Development of CVD Events in Patients with CKD

Deficiency of the micronutrient zinc is common in patients with chronic kidney disease (CKD). The aim of this review is to summarize evidence presented in literature for consolidation of current knowledge regarding zinc status in CKD patients, including those undergoing hemodialysis. Zinc deficiency is known to be associated with various risk factors for cardiovascular disease (CVD), such as increased blood pressure, dyslipidemia, type 2 diabetes mellitus, inflammation, and oxidative stress. Zinc may protect against phosphate-induced arterial calcification by suppressing activation of nuclear factor kappa light chain enhancer of activated B. Serum zinc levels have been shown to be positively correlated with T₅₀ (shorter T₅₀ indicates higher calcification propensity) in patients with type 2 diabetes mellitus as well as those with CKD. Additionally, higher intake of dietary zinc was associated with a lower risk of severe abdominal aortic calcification. In hemodialysis patients, the beneficial effects of zinc supplementation in relation to serum zinc and oxidative stress levels was demonstrated in a meta-analysis of 15 randomized controlled trials. Thus, evidence presented supports important roles of zinc regarding antioxidative stress and suppression of calcification and indicates that zinc intake/supplementation may help to ameliorate CVD risk factors in CKD patients.

Concurrent Heavy Metal Exposures and Idiopathic Dilated Cardiomyopathy: A Case-Control Study from the Katanga Mining Area of the Democratic Republic of Congo

Blood and/or urine levels of 27 heavy metals were determined by ICPMS in 41 patients with dilated cardiomyopathy (DCM) and 29 presumably healthy subjects from the Katanga Copperbelt (KC), in the Democratic Republic of Congo (DRC). After adjusting for age, gender, education level, and renal function, DCM probability was almost maximal for blood concentrations above 0.75 and 150 µg/dL for arsenic and copper, respectively. Urinary concentrations above 1 for chromium, 20 for copper, 600 for zinc, 30 for selenium, 2 for cadmium, 0.2 for antimony, 0.5 for thallium, and 0.05 for uranium, all in μg/g of creatinine, were also associated with increased DCM probability. Concurrent and multiple exposures to heavy metals, well beyond permissible levels, are associated with increased probability for DCM. Study findings warrant screening for metal toxicity in case of DCM and prompt public health measures to reduce exposures in the KC, DRC.

Zinc as a complementary treatment for cancer patients: a systematic review

Zinc is a trace element that plays an important role in the immune system and cell growth. The role of zinc in cancer treatment has been discussed for some time, however without reaching an evidenced-based consensus. Therefore, we aim to critically examine and review existing evidence on the role of zinc during cancer treatment. In January 2019, a systematic search was conducted searching five electronic databases (Embase, Cochrane, PsychINFO, CINAHL and PubMed) to find studies concerning the use, effectiveness and potential harm of zinc therapy on cancer patients. Out of initial 5244 search results, 19 publications concerning 23 studies with 1230 patients were included in this systematic review. The patients treated with zinc were mainly diagnosed with head and neck cancer and underwent chemo-, radio- or concurrent radio-chemotherapy. Interventions included the intake of different amounts of zinc supplements and oral zinc rinses. Outcomes (primary endpoints) investigated were mucositis, xerostomia, dysgeusia, pain, weight, dermatitis and oral intake of nutrients. Secondary endpoints were survival data, quality of life assessments and aspects of fatigue, immune responses and toxicities of zinc. The studies were of moderate quality reporting heterogeneous results. Studies have shown a positive impact on the mucositis after radiotherapy. No protection was seen against mucositis after chemotherapy. There was a trend to reduced loss of taste, less dry mouth and oral pain after zinc substitution. No impact was seen on weight, QoL measurements, fatigue, and survival. The risk of side effects from zinc appears to be relatively small. Zinc could be useful in the prevention of oral toxicities during irradiation. It does not help in chemotherapy-induced side effects.

The effect of curcumin and zinc co-supplementation on glycemic parameters in overweight or obese prediabetic subjects: A phase 2 randomized, placebo-controlled trial with a multi-arm, parallel-group design

Management of prediabetes is a critical step to prevent type-2 diabetes. Curcumin and zinc have been studied as an antioxidant, antiinflammatory, and antidiabetic agents. In this clinical trial, 84 subjects were randomized into curcumin (500 mg), zinc (30 mg), zinc and curcumin, and placebo groups for 90 days. At the baseline and the end of the study, the outcomes (fasting plasma glucose (FPG), 2-hour postprandial glucose (2hpp), HbA₁ C, insulin, insulin sensitivity (IS), insulin resistance (IR), β-cell function (BCF), weight, body mass index (BMI), dietary intake, and physical activity (PA)) were measured. A hypocaloric diet and PA were recommended for all subjects. In total, 82 subjects completed the study. After the intervention, dietary intake, PA, weight, and BCF% did not show a significant difference among the groups. However, subjects taking only zinc and zinc and curcumin groups experienced decreased BMI compared to the placebo (p = .01 and .007, respectively). The three treated groups had improved FPG (p = .01), 2hpp (p = .003), HbA1C (p = .004), insulin (p = .001), IS% (p = .001), and IR (p < .001) compared to the placebo. Based on these results, zinc and curcumin supplementation exerted a beneficial effect on several key glycemic parameters.

Zinc and/or Selenium Enriched Spirulina as Antioxidants in Growing Rabbit Diets to Alleviate the Deleterious Impacts of Heat Stress during Summer Season

Simple Summary

Heat stress in summer season impairs growth and causes heat-induced physiological stress in rabbits. Zinc acts as an antioxidant stress agent by inhibition of oxidation of macromolecules such as DNA as well as inhibition of inflammatory response, eventually resulting in the down-regulation of reactive oxygen species production. Selenium is a powerful biological anti-oxidant mineral. Spirulina is comparatively confined extreme protein (55–65%) and comprised all important amino acids, has wellbeing assistances, immuno-stimulatory influences and antiviral activity and ensured the capability to diminish heat stress impacts. In the current work, effects of dietary supplemental zinc and/ or selenium enriched spirulina (100 mg Zn-Sp/kg diet, 0.5 mg Se-Sp/kg diet or 100 mg Zn-Sp+ 0.5 mg Se-Sp, respectively) as antioxidants on growth performance, nutrient digestibility, plasma biochemicals and antioxidant status of New Zealand White growing rabbits under summer conditions were evaluated. The findings showed that the supplemented diets enhanced growth performance of rabbits at marketing, hot carcass weight, dressing percentage, high density lipoprotein cholesterol and total antioxidant capacity and reduced thio-barbituric acid reactive substances. Finally, dietary supplementation of 100 mg Zn-Sp, 0.5 mg Se-Sp or their combination could improve growth performance, nutrients digestibility and antioxidant status of heat stressed growing rabbits.

Abstract

Effects of dietary supplemental zinc and/ or selenium enriched spirulina (Zn-Sp, Se-Sp and Zn-Se-Sp, respectively) as antioxidants on growth performance, nutrient digestibility, plasma biochemicals and antioxidant status of growing rabbits under summer conditions were evaluated. A total of 160 New Zealand White male rabbits at six-weeks-old were randomly assigned to four groups. The first group received untreated diet (control). The other groups received diet supplemented with 100 mg Zn-Sp/kg diet, 0.5 mg Se-Sp/kg diet or 100 mg Zn-Sp+ 0.5 mg Se-Sp, respectively. The findings showed that the supplemented diets enhanced growth performance of rabbits at marketing. Rabbits fed Zn-Sp exhibited high dry and organic matter digestibilities while those fed Zn-Sp and Zn-Se-Sp diet supplemented achieved high crude protein digestibility. Rabbits fed diet supplemented with Zn-Se-Sp gave the highest hot carcass weight when competed with their counterparts. Zn-Sp and Zn-Se-Sp supplemented diets tended to promote dressing percentage. Low concentrations of plasma total cholesterol, LDL-cholesterol and VLDL-cholesterol were recorded by Se-Sp and Zn-Se-Sp groups. Rabbits fed Se-Sp, Zn-Se-Sp had the greatest HDL, plasma TAC and catalase and the lowest TBARs. Conclusively, dietary supplementation of 100 mg Zn-Sp, 0.5 mg Se-Sp or their combination could improve growth performance, nutrients digestibility and antioxidant status of heat stressed growing rabbits.

Zinc Preconditioning Provides Cytoprotection following Iodinated Contrast Media Exposure in In Vitro Models

Methods

Normal human proximal renal kidney cells (HK-2) were preconditioned with either increasing doses of ZnCl₂ or control. Following this preconditioning, cells were exposed to increasing concentrations of Iohexol 300 mg I₂/ml for four hours. Key outcome measures included cell survival (MTT colorimetric assay) and ROS generation (H₂DCFDA fluorescence assay).

Results

Contrast media induced a dose-dependent reduction in survival of HK-2 cells. Compared to control, contrast media at 150, 225, and 300 mg I₂/ml resulted in 69.5% (SD 8.8%), 37.3% (SD 4.8%), and 4.8% (SD 6.6%) cell survival, respectively (p < 0.001). Preconditioning with 37.5 μM and 50 μM ZnCl₂ increased cell survival by 173% (SD 27.8%) (p < 0.001) and 219% (SD 32.2%) (p < 0.001), respectively, compared to control preconditioning. Zinc preconditioning resulted in a reduction of ROS generation. Zinc pre-conditioning with 37.5 μM μM ZnCl₂ reduced ROS generation by 46% (p < 0.001) compared to control pre-conditioning.

Conclusions

Zinc preconditioning reduces oxidative stress following exposure to radiographic contrast media which in turn results in increased survival of renal cells. Translation of this in vitro finding in animal models will lay the foundation for future use of zinc preconditioning against contrast induced nephropathy.

Biomarkers of Zinc and Copper Status and Associated Factors in Outpatients with Ischemic and Non-Ischemic Heart Failure

Background: Few studies have explored the impact of ischemic and non-ischemic etiologies of heart failure and other factors associated with heart failure on zinc and copper status. This study examined zinc and copper status in 80 outpatients with ischemic (n = 36) and non-ischemic (n = 44) heart failure and associations with biodemographic, clinical, biochemical, and nutritional parameters.Materials: Biomarkers of plasma zinc and copper, copper-zinc ratio, 24-h urinary zinc excretion, ceruloplasmin, and dietary intake of zinc and copper were assessed. Plasma zinc and copper and urinary zinc were measured by inductively coupled plasma mass spectrometry (ICP-MS).Results: Patients with ischemic heart failure showed lower dietary zinc intake and higher dietary copper intake (both p = 0.02). Zinc and copper in plasma, copper-zinc ratio, ceruloplasmin, and 24-h urinary zinc excretion showed no statistical differences between the groups (all p ≥ 0.05). An inverse association was found between age (β =-0.001; p = 0.005) and the use of diuretics (β = -0.047; p = 0.013) and plasma zinc. Copper levels in plasma (β = 0.001; p < 0.001), and albumin (β = 0.090; p<0.001) were directly associated with plasma zinc. A positive association was found between ceruloplasmin (β = 0.011; p < 0.001), gamma-glutamyl transferase (β = 0.001; p < 0.001), albumin (β = 0.077; p = 0.001), and high-sensitivity c-reactive protein (β = 0.001; p = 0.024) and plasma copper.Conclusion: Zinc and copper biomarkers in clinically stable patients with heart failure did not seem to be responsive to the differences in zinc and copper intake observed in this study, regardless of heart failure etiology. The predictors of plasma zinc and copper levels related to oxidative stress and inflammation should be monitored in heart failure clinical practice.

Protective effects of green and chemical zinc oxide nanoparticles on testis histology, sperm parameters, oxidative stress markers and androgen production in rats treated with cisplatin

Cancer treatment with cisplatin (CP) is associated with adverse side effects on male reproductive tissues. Although beneficial effects of zinc oxide nanoparticles (ZnO NPs) in cancer therapy have received considerable attention, data related to the protective effects of green ZnO NPs against CP-induced male reproductive dysfunctions are limited. Forty-five rats were divided into 9 groups including G1 (control), G2 (sham), G3 (ZnO bulk), G4 (green ZnO NPs), G5 (chemical ZnO NPs), G6 (CP), G7 (CP + ZnO bulk), G8 (CP + green ZnO NPs), and G9 (CP + chemical ZnO NPs). CP was administrated (5 mg/kg/week) for 4 weeks, and animals were simultaneously treated with different forms of ZnO (5 mg/kg/day). Testis histology, sperm parameters, oxidative stress markers, testosterone concentration, and expression of genes related in steroidogenesis were analyzed in different experimental groups. Testis tissue damage and epididymal sperm disorders induced by CP attenuated when animals were treated with different forms of ZnO, especially green ZnO NPs. Decreased testosterone concentration and increased MDA level in CP-treated rats were reversed following administration different forms of ZnO, especially green and chemical ZnO NPs. Co-administration of ZnO NPs to CP-treated rats restored the suppressive effects of CP on activities of antioxidant enzymes (SOD, GPX, CAT) and the transcription of the STAR gene. None of the ZnO forms had a significant regulatory effect on the expression of CYP11A1 in CP-treated rats. The results showed that in most of the evaluated factors, green ZnO NPs showed a greater protective effect than other forms of ZnO.

Nutraceutical Strategies for Suppressing NLRP3 Inflammasome Activation: Pertinence to the Management of COVID-19 and Beyond

Inflammasomes are intracellular protein complexes that form in response to a variety of stress signals and that serve to catalyze the proteolytic conversion of pro-interleukin-1β and pro-interleukin-18 to active interleukin-1β and interleukin-18, central mediators of the inflammatory response; inflammasomes can also promote a type of cell death known as pyroptosis. The NLRP3 inflammasome has received the most study and plays an important pathogenic role in a vast range of pathologies associated with inflammation-including atherosclerosis, myocardial infarction, the complications of diabetes, neurological and autoimmune disorders, dry macular degeneration, gout, and the cytokine storm phase of COVID-19. A consideration of the molecular biology underlying inflammasome priming and activation enables the prediction that a range of nutraceuticals may have clinical potential for suppressing inflammasome activity-antioxidants including phycocyanobilin, phase 2 inducers, melatonin, and N-acetylcysteine, the AMPK activator berberine, glucosamine, zinc, and various nutraceuticals that support generation of hydrogen sulfide. Complex nutraceuticals or functional foods featuring a number of these agents may find utility in the prevention and control of a wide range of medical disorders.

Structure and Properties of Biodegradable PLLA/ZnO Composite Membrane Produced via Electrospinning

These days, composite materials based on polymers and inorganic nanoparticles (NPs) are widely used in optoelectronics and biomedicine. In this work, composite membranes of polylactic acid and ZnO NPs containing 5–40 wt.% of the latter NPs were produced by means of electrospinning. For the first time, polymer material loaded with up to 40 wt.% of ZnO NPs (produced via laser ablation in air and having non-modified surface) was used to prepare fiber-based composite membranes. The morphology, phase composition, mechanical, spectral and antibacterial properties of the membranes were tested by a set of analytical techniques including SEM, XRD, FTIR, UV-vis, and photoluminescence spectroscopy. Antibacterial activity of the materials was evaluated following standard procedures (ISO 20743:2013) and using S. aureus and E. coli bacteria. It is shown that incorporation of 5–10 wt.% of NPs led to improved mechanical properties of the composite membranes, while further increase of ZnO content up to 20 wt.% and above resulted in their noticeable deterioration. At the same time, the antibacterial properties of ZnO-rich membranes were more pronounced, which is explained by a larger number of surface-exposed ZnO NPs, in addition to those embedded into the bulk of fiber material.

Time- and Zinc-Related Changes in Biomechanical Properties of Human Colorectal Cancer Cells Examined by Atomic Force Microscopy

Simple Summary

We aimed to study how cellular zinc status (adequate vs. deficiency), closely related to colorectal cancer, does affect the nanomechanical properties of cell lines HT-29 and HT-29-MTX during their early proliferation (24–96 h). These properties and their variations can be characterized by means of Atomic Force Microscopy (AFM), a technique that allows perpendicular indentation of cells with a sharp nanometric tip, under controlled speed and load, while recording the real time variation of tip-to-cell interacting forces on approach, contact, and retraction segments. From each of these sections, complete information about the respective elastic modulus, relaxation behavior, and adhesion is extracted, thus identifying cell line- and zinc-related nanomechanical fingerprints. Our results show how the impact of zinc deficiency on the mechanical response of the cells underlines the relevance of monitoring the nutritional zinc status of tumor samples when analyzing cancerous tissues or single cells with AFM, particularly regarding the development and validation of biomechanical fingerprints as diagnostic markers for cancer.

Abstract

Monitoring biomechanics of cells or tissue biopsies employing atomic force microscopy (AFM) offers great potential to identify diagnostic biomarkers for diseases, such as colorectal cancer (CRC). Data on the mechanical properties of CRC cells, however, are still scarce. There is strong evidence that the individual zinc status is related to CRC risk. Thus, this study investigates the impact of differing zinc supply on the mechanical response of the in vitro CRC cell lines HT-29 and HT-29-MTX during their early proliferation (24–96 h) by measuring elastic modulus, relaxation behavior, and adhesion factors using AFM. The differing zinc supply severely altered the proliferation of these cells and markedly affected their mechanical properties. Accordingly, zinc deficiency led to softer cells, quantitatively described by 20–30% lower Young’s modulus, which was also reflected by relevant changes in adhesion and rupture event distribution compared to those measured for the respective zinc-adequate cultured cells. These results demonstrate that the nutritional zinc supply severely affects the nanomechanical response of CRC cell lines and highlights the relevance of monitoring the zinc content of cancerous cells or biopsies when studying their biomechanics with AFM in the future.

The Way to a Human's Brain Goes Through Their Stomach: Dietary Factors in Major Depressive Disorder

Globally, more than 250 million people are affected by depression (major depressive disorder; MDD), a serious and debilitating mental disorder. Currently available treatment options can have substantial side effects and take weeks to be fully effective. Therefore, it is important to find safe alternatives, which act more rapidly and in a larger number of patients. While much research on MDD focuses on chronic stress as a main risk factor, we here make a point of exploring dietary factors as a somewhat overlooked, yet highly promising approach towards novel antidepressant pathways. Deficiencies in various groups of nutrients often occur in patients with mental disorders. These include vitamins, especially members of the B-complex (B6, B9, B12). Moreover, an imbalance of fatty acids, such as omega-3 and omega-6, or an insufficient supply with minerals, including magnesium and zinc, are related to MDD. While some of them are relevant for the synthesis of monoamines, others play a crucial role in inflammation, neuroprotection and the synthesis of growth factors. Evidence suggests that when deficiencies return to normal, changes in mood and behavior can be, at least in some cases, achieved. Furthermore, supplementation with dietary factors (so called "nutraceuticals") may improve MDD symptoms even in the absence of a deficiency. Non-vital dietary factors may affect MDD symptoms as well. For instance, the most commonly consumed psychostimulant caffeine may improve behavioral and molecular markers of MDD. The molecular structure of most dietary factors is well known. Hence, dietary factors may provide important molecular tools to study and potentially help treat MDD symptoms. Within this review, we will discuss the role of dietary factors in MDD risk and symptomology, and critically discuss how they might serve as auxiliary treatments or preventative options for MDD.

Does Herbal and/or Zinc Dietary Supplementation Improve the Antioxidant and Mineral Status of Lambs with Parasite Infection?

This study was conducted to evaluate the effect of feed supplementation with a medicinal herbs mixture (Hmix) and organic zinc (Zn), alone or in combination, on the antioxidant responses and mineral status of lambs infected with the gastrointestinal nematode parasite Haemonchus contortus. A total of 24 experimentally infected lambs were randomly allocated to 1 of 4 dietary treatments (n = 6). The diets included an unsupplemented control diet (CON) and the CON further supplemented with Hmix, Zn, or both Hmix + Zn. Antioxidant enzymes activities, lipid peroxidation, total antioxidant capacity (TAC) and microelement (Zn, Cu, Fe, Mn) concentrations were analyzed in serum, liver, kidney, and intestinal mucosa. Zinc treatment elevated the superoxide dismutase activities in the duodenal mucosa and ileal TAC. Intake of Hmix resulted in higher kidney and ileal catalase activity and also influenced the TAC of the liver and intestinal mucosa. The inclusion of Hmix or Zn alone into the diet increased glutathione peroxidase activity in the blood, liver and duodenal mucosa. Tissue mineral uptake was not affected by herbal supplementation. Organic Zn intake increased the serum and liver Zn levels and influenced the Cu concentration in duodenal mucosa. Dietary supplementation with Hmix and/or Zn might promote the antioxidant status of lambs infected with Haemonchus spp.

The role of labile Zn2+ and Zn2+-transporters in the pathophysiology of mitochondria dysfunction in cardiomyocytes

An important energy supplier of cardiomyocytes is mitochondria, similar to other mammalian cells. Studies have demonstrated that any defect in the normal processes controlled by mitochondria can lead to abnormal ROS production, thereby high oxidative stress as well as lack of ATP. Taken into consideration, the relationship between mitochondrial dysfunction and overproduction of ROS as well as the relation between increased ROS and high-level release of intracellular labile Zn²⁺, those bring into consideration the importance of the events related with those stimuli in cardiomyocytes responsible from cellular Zn²⁺-homeostasis and responsible Zn²⁺-transporters associated with the Zn²⁺-homeostasis and Zn²⁺-signaling. Zn²⁺-signaling, controlled by cellular Zn²⁺-homeostatic mechanisms, is regulated with intracellular labile Zn²⁺ levels, which are controlled, especially, with the two Zn²⁺-transporter families; ZIPs and ZnTs. Our experimental studies in mammalian cardiomyocytes and human heart tissue showed that Zn²⁺-transporters localizes to mitochondria besides sarco(endo)plasmic reticulum and Golgi under physiological condition. The protein levels as well as functions of those transporters can re-distribute under pathological conditions, therefore, they can interplay among organelles in cardiomyocytes to adjust a proper intracellular labile Zn²⁺ level. In the present review, we aimed to summarize the already known Zn²⁺-transporters localize to mitochondria and function to stabilize not only the cellular Zn²⁺ level but also cellular oxidative stress status. In conclusion, one can propose that a detailed understanding of cellular Zn²⁺-homeostasis and Zn²⁺-signaling through mitochondria may emphasize the importance of new mitochondria-targeting agents for prevention and/or therapy of cardiovascular dysfunction in humans.

A mixture of chloromethylisothiazolinone and methylisothiazolinone impairs rat vascular smooth muscle by depleting thiols and thereby elevating cytosolic Zn2+ and generating reactive oxygen species

Chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) are biocidal preservatives and the active ingredients in Kathon CG, which contains ca. 1.5% mixture of CMIT and MIT at a ratio of 3:1 (CMIT/MIT). CMIT/MIT was misused as humidifier disinfectant products, which caused serious health problems in Korea. Here, the vascular effects of CMIT/MIT were investigated to evaluate claims of putative cardiovascular toxicity observed in humidifier disinfectant users. CMIT/MIT did not affect the basal tension of the rat thoracic aorta up to 2.5 μg/mL in myograph experiments. Instead, pretreatment with CMIT/MIT impaired phenylephrine- or 5-hydroxytryptamine-induced vasoconstriction in a range of 0.5-2.5 μg/mL, which was largely irreversible and not recovered by washing out the CMIT/MIT. Similarly, the application of CMIT/MIT to pre-contracted aorta caused a gradual loss of tension. In primary cultured vascular smooth muscle cells (VSMCs), CMIT/MIT caused thiol depletion, which in turn led to cytosolic Zn²⁺ elevation and reactive oxygen species (ROS) formation. CMIT/MIT-induced shrinkage, detachment, and lysis of VSMCs depending on the concentration and the treatment time. All events induced by CMIT/MIT were prevented by a thiol donor N-acetylcysteine (NAC). Cytolysis could be inhibited by a Zn²⁺ chelator TPEN and a superoxide scavenger TEMPOL, whereas they did not affect shrinkage and detachment. In accordance with these results, CMIT/MIT-exposed aortas exhibited dissociation and collapse of tissue in histology analysis. Taken together, CMIT/MIT causes functional impairment and tissue damage to blood vessels by depleting thiol and thereby elevating cytosolic Zn²⁺ and generating ROS. Therefore, exposure to CMIT/MIT in consumer products may be a risk factor for cardiovascular disorders.

Association between Serum Zinc Levels and Clinical Index or the Body Composition in Incident Hemodialysis Patients

Background: The relationships between serum zinc levels and body composition or clinical outcomes of incident hemodialysis (HD) patients remain unclear. Methods: This prospective observational study examined the relationships between serum zinc levels and clinical indexes, including body composition, in 142 incident HD patients using a bioelectrical impedance analysis. Patients were divided into three groups according to baseline serum zinc levels: tertile, <45, 45–59, and ≥60 µg/dL. The reference group was set as ≥60 µg/dL. Cox’s regression analysis was performed to investigate the relationships between serum zinc categories and cardiovascular events and all-cause mortality after adjustments for potential confounders. Results: Serum zinc levels positively correlated with the nutritional index and negatively correlated with fluid volume markers. In a mean follow-up of 2.5 years, there were 20 cases of cardiovascular events and 15 of all-cause mortality. In the Cox’s regression analysis for cardiovascular events and all-cause mortality, the hazard ratio increased with a decrease in serum zinc levels, but was not significant. Conclusion: Serum zinc levels were associated with nutritional and fluid volume markers in incident HD patients. To clarify the relationship between serum zinc levels and cardiovascular events or mortality, further studies with a larger number of cases will be necessary.

Diabetes and zinc dyshomeostasis: Can zinc supplementation mitigate diabetic complications?

Zinc present in the islet cells of the pancreas is crucial for the synthesis, storage, and secretion of insulin. The excretion of large amounts of zinc from the body is reported in diabetic situations. Zinc depletion and increased oxidative stress have a major impact on the pathogenesis of diabetic complications. It would be most relevant to ascertain if intervention with supplemental zinc compensating for its depletion would beneficially mitigate hyperglycemia and the attendant metabolic abnormalities, and secondary complications in diabetes. An exhaustive literature search on this issue indicates: (1) Concurrent hypozincemia and decreased tissue zinc stores in diabetes as a result of its increased urinary excretion and/or decreased intestinal absorption, (2) Several recent experimental studies have documented that supplemental zinc has a potential hypoglycemic effect in the diabetic situation, and also beneficially modulate the attendant metabolic abnormalities and compromised antioxidant status, and (3) Supplemental zinc also alleviates renal lesions, cataract and the risk of cardiovascular disease accompanying diabetes mellitus, and help restore gastrointestinal health in experimental diabetes. These studies have also attempted to identify the precise mechanisms responsible for zinc-mediated beneficial effects in diabetic situation. The evidence discussed in this review highlights that supplemental zinc may significantly contribute to its clinical application in the management of diabetic hyperglycemia and related metabolic abnormalities, and in the alleviation of secondary complications resulting from diabetic oxidative stress.

Antitumoral Properties of the Nutritional Supplement Ocoxin Oral Solution: A Comprehensive Review

Ocoxin Oral Solution (OOS) is a nutritional supplement whose formulation includes several plant extracts and natural products with demonstrated antitumoral properties. This review summarizes the antitumoral action of the different constituents of OOS. The action of this formulation on different preclinical models as well as clinical trials is reviewed, paying special attention to the mechanism of action and quality of life improvement properties of this nutritional supplement. Molecularly, its mode of action includes a double edge role on tumor biology, that involves a slowdown in cell proliferation accompanied by cell death induction. Given the safety and good tolerability of OOS, and its potentiation of the antitumoral effect of other standard of care drugs, OOS may be used in the oncology clinic in combination with conventional therapies.

Recent aspects of the effects of zinc on human health

Zinc (Zn) is one of the most important essential nutrients of great public health significance. It is involved in numerous biological functions and it is considered as a multipurpose trace element, due to its capacity to bind to more than 300 enzymes and more than 2000 transcriptional factors. Its role in biochemical pathways and cellular functions, such as the response to oxidative stress, homeostasis, immune responses, DNA replication, DNA damage repair, cell cycle progression, apoptosis and aging is significant. Zn is required for the synthesis of protein and collagen, thus contributing to wound healing and a healthy skin. Metallothioneins are metal-binding proteins and they are potent scavengers of heavy metals, including Zn, and protect the organism against stress. Zn deficiency is observed almost in 17% of the global population and affects many organ systems, leading to dysfunction of both humoral and cell-mediated immunity, thus increasing the susceptibility to infection. This review gives a thorough insight into the most recent evidence on the association between Zn biochemistry and human pathologies, epigenetic processes, gut microbial composition, drug targets and nanomedicine.

Zinc as a Therapeutic Agent in Bone Regeneration

Zinc is an essential mineral that is required for normal skeletal growth and bone homeostasis. Furthermore, zinc appears to be able to promote bone regeneration. However, the cellular and molecular pathways through which zinc promotes bone growth, homeostasis, and regeneration are poorly understood. Zinc can positively affect chondrocyte and osteoblast functions, while inhibiting osteoclast activity, consistent with a beneficial role for zinc in bone homeostasis and regeneration. Based on the effects of zinc on skeletal cell populations and the role of zinc in skeletal growth, therapeutic approaches using zinc to improve bone regeneration are being developed. This review focuses on the role of zinc in bone growth, homeostasis, and regeneration while providing an overview of the existing studies that use zinc as a bone regeneration therapeutic.

In vitro Anti-Inflammatory and Anti-Oxidative Stress Activities of Kushenol C Isolated from the Roots of Sophora flavescens

Kushenol C (KC) is a prenylated flavonoid isolated from the roots of Sophoraflavescens aiton. Little is known about its anti-inflammatory and anti-oxidative stress activities. Here, we investigated the anti-inflammatory and anti-oxidative stress effects of KC in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, and tert-butyl hydroperoxide (tBHP)-induced oxidative stress in HaCaT cells. The results demonstrated that KC dose-dependently suppressed the production of inflammatory mediators, including NO, PGE₂, IL-6, IL1β, MCP-1, and IFN-β in LPS-stimulated RAW264.7 macrophages. The study demonstrated that the inhibition of STAT1, STAT6, and NF-κB activations by KC might have been responsible for the inhibition of NO, PGE₂, IL-6, IL1β, MCP-1, and IFN-β in the LPS-stimulated RAW264.7 macrophages. KC also upregulated the expression of HO-1 and its activities in the LPS-stimulated RAW264.7 macrophages. The upregulation of Nrf2 transcription activities by KC in the LPS-stimulated RAW264.7 macrophages was demonstrated to be responsible for the upregulation of HO-1 expression and its activity in LPS-stimulated RAW264.7 macrophages. In HaCaT cells, KC prevented DNA damage and cell death by upregulating the endogenous antioxidant defense system involving glutathione, superoxide dismutase, and catalase, which prevented reactive oxygen species production from tert-butyl hydroperoxide (tBHP)-induced oxidative stress in HaCaT cells. The upregulated activation of Nrf2 and Akt in the PI3K-Akt signaling pathway by KC was demonstrated to be responsible for the anti-oxidative stress activity of KC in HaCaT cells. Collectively, the study suggests that KC can be further investigated as a potential anti-inflammatory candidate for the treatment of inflammatory diseases.

Impact of zinc oxide nanoparticles on thioredoxin-interacting protein and asymmetric dimethylarginine as biochemical indicators of cardiovascular disorders in gamma-irradiated rats

Nanoparticle is a microscopic particle that has been existed in a wide range of biotechnological purposes. Zinc oxide nanoparticles (ZnO-NPs) have fewer environmental hazards and have shown positive impacts in the medical field. This work aimed to observe the effects of low and high doses of ZnO-NPs on heart injury induced by ionizing radiation (IR). Animals were irradiated by 8 Gy of gamma rays and ZnO-NPs (10 and 300 mg/Kg/day) were orally delivered to rats 1 hour after irradiation. Animals were dissected on 15th day postirradiation. Data showed that the oxidative damage resulted from radiation exposure, appeared by marked increments in the malondialdehyde (MDA) content and the level and protein expression of thioredoxin-interacting protein (TXNIP) with a noticeable decline in the level and expression of thioredoxin 1 (Trx-1) and thioredoxin reductase (TrxR), as well as glutathione (GSH) level and the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Moreover, radiation-induced inflammation, manifested by a noticeable elevation in the level of tumor necrotic factor-alpha (TNF-α), interleukin-18 (IL-18), and C-reactive protein (CRP). Additionally, endothelial dysfunction marked with a high level of asymmetric dimethylarginine (ADMA), total nitrite/nitrate (NOx), intercellular adhesion molecule 1 (ICAM-1), homocysteine (Hcy), creatine kinase (CK-MB), cardiac troponin-I (cTn-I), and lactate dehydrogenase (LDH). In addition, a decrease of zinc (Zn) level in the cardiac tissue was recorded. ZnO-NPs treatment (10 mg/kg) mitigated the oxidative stress and inflammation effects on the cardiovascular tissue through the positive modulations in the studied parameters. In contrast, ZnO-NPs treatment (300 mg/kg) induced cardiovascular toxicity of normal rats and elevated the deleterious effects of radiation. In conclusion, ZnO-NPs at a low dose could mitigate the adverse effects on cardiovascular tissue induced by radiation during its applications, while the high dose showed morbidity and mortality in normal and irradiated rats.

Zinc at the crossroads of exercise and proteostasis

Zinc is an essential element for all forms of life, and one in every ten human proteins is a zinc protein. Zinc has catalytic, structural and signalling functions and its correct homeostasis affects many cellular processes. Zinc deficiency leads to detrimental consequences, especially in tissues with high demand such as skeletal muscle. Zinc cellular homeostasis is tightly regulated by different transport and buffer protein systems. Specifically, in skeletal muscle, zinc has been found to affect myogenesis and muscle regeneration due to its effects on muscle cell activation, proliferation and differentiation. In relation to skeletal muscle, exercise has been shown to modulate zinc serum and urinary levels and could directly affect cellular zinc transport. The oxidative stress induced by exercise may provide the basis for the mild zinc deficiency observed in athletes and could have severe consequences on health and sport performance. Proteostasis is induced during exercise and zinc plays an essential role in several of the associated pathways.

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Zinc deficiency could be a crucial issue in sport performance for athletes.

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Exercise could modulate zinc serum and cellular homeostasis.

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Zinc is part of proteostatic systems critical during exercise.

Advances of Zinc Signaling Studies in Prostate Cancer

Prostate cancer (PCa) is one of the most common cancers and the second leading cause of cancer-related death among men worldwide. Despite progresses in early diagnosis and therapeutic strategies, prognosis for patients with advanced PCa remains poor. Noteworthily, a unique feature of healthy prostate is its highest level of zinc content among all soft tissues in the human body, which dramatically decreases during prostate tumorigenesis. To date, several reviews have suggested antitumor activities of zinc and its potential as a therapeutic strategy of PCa. However, an overview about the role of zinc and its signaling in PCa is needed. Here, we review literature related to the content, biological function, compounds and clinical application of zinc in PCa. We first summarize zinc content in prostate tissue and sera of PCa patients with their clinical relevance. We then elaborate biological functions of zinc signaling in PCa on three main aspects, including cell proliferation, death and tumor metastasis. Finally, we discuss clinical applications of zinc-containing compounds and proteins involved in PCa signaling pathways. Based on currently available studies, we conclude that zinc plays a tumor suppressive role and can serve as a biomarker in PCa diagnosis and therapies.

Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence

Vitamins and minerals are essential to humans as they play essential roles in a variety of basic metabolic pathways that support fundamental cellular functions. In particular, their involvement in energy-yielding metabolism, DNA synthesis, oxygen transport, and neuronal functions makes them critical for brain and muscular function. These, in turn, translate into effects on cognitive and psychological processes, including mental and physical fatigue. This review is focused on B vitamins (B1, B2, B3, B5, B6, B8, B9 and B12), vitamin C, iron, magnesium and zinc, which have recognized roles in these outcomes. It summarizes the biochemical bases and actions of these micronutrients at both the molecular and cellular levels and connects them with cognitive and psychological symptoms, as well as manifestations of fatigue that may occur when status or supplies of these micronutrients are not adequate.

Zinc dysregulation in cancers and its potential as a therapeutic target

Zinc is an essential element and serves as a structural or catalytic component in many proteins. Two families of transporters are involved in maintaining cellular zinc homeostasis: the ZIP (SLC39A) family that facilitates zinc influx into the cytoplasm, and the ZnT (SLC30A) family that facilitates zinc efflux from the cytoplasm. Zinc dyshomeostasis caused by the dysfunction of zinc transporters can contribute to the initiation or progression of various cancers, including prostate cancer, breast cancer, and pancreatic cancer. In addition, intracellular zinc fluctuations lead to the disturbance of certain signaling pathways involved in the malignant properties of cancer cells. This review briefly summarizes our current understanding of zinc dyshomeostasis in cancer, and discusses the potential roles of zinc or zinc transporters in cancer therapy.